The invention pertains to a method and circuit for the digital deflection correction of television picture tubes.
Television receivers, more particularly color television receivers employing digital processing of the composite color signal have been described, for example, in the technical journal "Electronics" of Aug. 11, 1981, on pages 97 to 103. On page 101 there is described the geometry correction in use since the early stages of television engineering. This correction is required in conventional types of television picture tubes because the viewing screen is not a spherical surface. As with conventional television receivers, geometry correction is also achieved in television receivers employing digital signal processing, in that both the horizontal and the vertical deflection signals are corrected correspondingly. This correction is known as parabolic correction to those skilled in the art.
This kind of geometry correction can only be realized up to a certain extent at a reasonable cost. Accordingly a visible amount of error results. Moreover, the usual geometry correction cannot be carried out merely by electrically influencing the electric deflection signal but, in addition thereto, requires influencing the magnetic field produced by the deflection coils.